Maximally Redundant Trees
for IP/LDP Unicast,
draft-ietf-rtgwg-mrt-frr-architecture-01
Algorithms
draft-enyedi-rtgwg-mrt-frr-algorithm-01
for Multicast,
draft-atlas-rtgwg-mrt-mc-arch-00
Alia Atlas, Gábor Enyedi, András Császár, Robert Kebler,
IJsbrand Wijnands, Maciek Konstantynowicz
Russ White, Mike Shand
IETF 84, Vancouver, B.C.
IETF 84 RTGWG: 31 July 2012
draft-ietf-rtgwg-mrt-frr-architecture-01
1
Quick Status:
MRT for IP/LDP Unicast Fast-Reroute
• Well understood and documented
• Plan for IGP Extensions:
– Use a flag to show MRT support and indicate all
associated information as a template. Keep it
simple.
• Two forwarding options – LDP or IP-in-IP
• Associated algorithms all implemented and
verified.
IETF 84 RTGWG: 31 July 2012
draft-ietf-rtgwg-mrt-frr-architecture-01
2
Quick Status:
MRT Algorithms
• Implementation of all MRT algorithms for
modeling is done.
• Analysis underway to compare/contrast:
– MRT alternates (slight variants of algorithm)
– Not-via alternates
– Optimal possible
– Remote-LFA
• More topologies are better – anonymized is
fine. Individualized results can be available.
IETF 84 RTGWG: 31 July 2012
draft-ietf-rtgwg-mrt-frr-architecture-01
3
Preliminary Analysis:
Interlocking Rings
Avg. alternate path length
8.4
8.2
8
7.8
7.6
7.4
80.4%
coverage
7.2
7
6.8
6.6
6.4
MRT
lowpoint
IETF 84 RTGWG: 31 July 2012
MRT bitmap MRT stack
spf
spf
draft-ietf-rtgwg-mrt-frr-architecture-01
Optimum
alternate
Not-via to Remote LFA
nnh
4
Preliminary Analysis:
Example Comparison
Minimum GADAG root,
Avg. alternate path length
300
93.75%
coverage
250
200
150
100
50
0
MRT
lowpoint
IETF 84 RTGWG: 31 July 2012
MRT bitmap MRT stack
spf
spf
draft-ietf-rtgwg-mrt-frr-architecture-01
Optimum
alternate
Not-via to Remote LFA
nnh
5
Quick Status:
MRT for Multicast Fast-Reroute & Live-Live
• Architecture understood
– Improving live-live reconvergence methods
• Working on protocol drafts for the
mechanisms.
• Looking for feedback & discussion.
IETF 84 RTGWG: 31 July 2012
draft-ietf-rtgwg-mrt-frr-architecture-01
6